If you are referring to Issue Management related to post-deployment problems, that should fall under your company's standard Problem Management policies and processes. Regarding a contingency plan for failed deployments, the most common approach is a rollback to the previous (working) state so you'd need to define the criteria for executing this rollback and design the processes and tools to support such a rollback taking into account that data might have "drifted" between the time of the last backup and the time of rollback.